Looking for a laser and I have some questions

[SamN]

First off, I'd like to say what a cool forum, I was reviewing some lasers and companies and stumbled across this site numerous times so I thought I'd sign up and ask the questions I have. I appreciate your help on the below.

I hope this is the correct section to post, I was searching and decided this was the most appropriate section as I have a few general questions.

I have read the stickies but I didn't get a definitive answer, perhaps I didn't search well enough but I personally prefer a personal answer from the experienced members.

I'm not looking to burn things/pop baloons etc, I just like seeing how far I can get the laser to go, I own a green 10mw laser although I suspect the output is not that good, it also ran out of AAA batteries really fast and got hot quick.

1. I live in the UK, so I'd prefer to purchase from a UK seller, a few sites I found had bad reviews from this forum so I'd like some top sellers if possible, if not I suppose I can can try the US and hope to win the customs gamble.

2. I'm looking to purchase no more than a 50mw green handheld laser, the driving factors for me are a long distance, good battery life and a really noticeable beam. I mostly experiment at night.

3. I'm more than willing to purchase safety goggles and I read the sticky in the safety and legal section, my question is can you damage your eyes just looking at the laser, even if I'm aiming it at a wall or in the night, can I still damage my eyes? I'm not really going to start reflecting it or doing anything with a chance of direct exposure to my eye although I guess I should get some goggles anyway, - As question 1 are there any good retailers of laser protective eye-wear?

That's pretty much it, as you can tell I'm still a first timer, but I just have a fascination for lasers, I don't want to go over the top but I'd like a laser I can get out a night and have an awesome green beam for miles

Thanks for your time guys.

 

[RA_pierce]

If you haven't already, check out the Buy, Sell, Trade section.
You may find someone located in the UK selling what you want.

There are many options for 50mW green lasers and the quality can vary as much as price.

One of the newest developments in green laser technology is the avialability of 50mW direct green diodes.
They have several advantages over the DPSS greens we normally play with including superior stability, smaller size, superior physical durability, and efficiency. Also, with a good lens, you can achieve lower divergence than with DPSS pointers (which means the useful range is greater).
At 520nm (versus the 532nm of common DPSS greens) the wavelength will appear very bright in daylight or at night (the human eye is most sensitive to green light).
The disadvantage is the price. The diode alone will cost you about $150USD and you will need to find someone to build it for you if you do not wish to go the DIY route.

If you give us a price range that sounds reasonable to you we will be able to provide more relevant recommendations.
50mW is an excellent choice, in my opinion, for a green pointer. It will be more than adequate for use in rural night skies and will still do the job in urban areas with lots of light pollution - without drawing too much attention or blasting your eyeballs out.

Welcome and good luck finding what you want.

 

[SamN]

Thanks for that response RA_pierce, you started to get a bit to technical for me.

The one I bought before cost me like $20 from Amazon, the beam and brightness was awesome, however it got hot and the battery life was terrible. I suppose I just want to upgrade to a pre-built 50mw with some good batter life (maybe rechargeable if that exists?), I don't want a custom build for those prices but I was looking at around £40-£50 so around $80.

 

[Sigurthr]

To answer your safety question, yes you can injure your eyesight by looking at the dot on the wall if conditions are right. There are several factors at play;

Reflectivity of the target surface - all surfaces reflect to some extent, not just "reflective" surfaces as we know them. Angle of incidence matters greatly, as even a diffuse reflection from a surface can be hazardous if the exit vector is towards eyes or specularly reflective material.

Distance from target surface. Uncollimated light follows the inverse square rule.

Output power of the laser

Power density of the beam at the target. A 100mW spot that is 500sqcm probably isn't going to do damage when shined on a diffuse reflector.


That all being said 50mW of green viewed on a non-white/blue/green matte surface from more than 2meters away with the laser 90degrees to the plane of the target should be safe enough to view with naked eyes.

 

[Rotten John]

It sounds like your laser is already over 50mW. Bright beam, host heating up quickly, and batteries dying fast all point to >80mW laser. And with a >80mW laser you really need proper eye protection.

What you could do is remove the module, and place it into a flashlight host kit. It will have better heat sinking, and you can use a larger, rechargeable, battery.